Value depends on scarcity. In the world of human reproduction, the most valuable entity is the fertile female—specifically, her eggs and womb.

The fierce politics surrounding female fecundity and women’s reproductive rights rests not only on a woman’s ability to create new life, but also on the incredible amount of commitment and risk involved when her eggs and womb are accessed for procreation. Since women are fertile for a shorter period than men, since gestation takes 40 long weeks, and since labor and delivery pose life-threatening risks, young women will always face disproportionately high demands for access to their bodies. But those demands are rising in unexpected ways, and from unexpected people.

Historically, it was understood that sex created babies. Cultural scripts thus emerged that valued and preferred certain types of sex and male-female relations. The profession of prostitution has always been highly stigmatized for this reason. As we’ve learned the hard way, when female prostitutes engage with their clients, fatherless children can be born, growing up distinctly disadvantaged.

By far, men have always been the main buyers of sexual access to fertile females. Women virtually never pay for sexual access to either gender. Women and girls make up the overwhelming majority of prostitutes and escorts, and men overwhelmingly make up the clientele. This is true for every human culture, in every period in history. And it has everything to do with reproduction and the scarcity of the fertile female.

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Rape is another example of unbalanced behavior between the genders. Although women do rape, men force sexual access against their victims’ will much more often—and their victims are predominantly young (as in fertile) women. Randy Thornhill and anthropologist Craig T. Palmer in their 2000 book A Natural History of Rape: Biological Bases of Sexual Coercion describe rape (and prostitution) as “gene promotion strategies” that men use when legitimate, consensual sex is not possible. A man that is unable to engage a fertile female in legitimate consensual sex may face the dilemma of using force, monetary incentives or facing extinction.

We teach our daughters a script of warning so they can anticipate these established sexual predators. Oprah broadcasts a list of safety tips for women to avoid them. Parents forbid their teenage daughters from a whole range of activities where her sexual safety may be threatened. We make movies about these predators. We have derogatory names for them. We have a sense of who they are, where they lurk, and what to do to avoid them. We do these things because we care about the health of women and know that their well-being, and the well-being of children, depends on whether they conceive babies in the context of love and companionship.

But now there are new predators on the scene, for whom we do not have a script. There are new characters eager to exploit our daughters’ bodies, who enjoy unsullied reputations, passing detection even as they blatantly hunt for eggs and wombs with checkbooks in hand. And historically they have been the people women should fear the least.

These new players vying for access to young women’s bodies are older or infertile women, and gay men—quite often our friends and members of our family.

A friend of mine, for example, had a bizarre encounter with a regular customer at the restaurant where she waits tables. A middle-aged woman, as politely as she could, asked my friend if she had ever considered becoming an egg donor—and then asked specifically if she would consider becoming her egg donor. Since my friend—Jewish, with blue eyes and straight hair—was apparently a rare catch, this woman wanted her babies.

Another friend of mine was put under a great deal of pressure by her aunt who married in her late thirties and had trouble conceiving. The aunt desperately wanted a child, and preferred to have a genetic relationship with the child, so she aggressively pressured her niece to “donate” eggs to her. If she had agreed, my friend would have become the biological mother of her social cousin.

By neutering ourselves in our youth via contraception and abortion, women have increased the scarcity of the fertile female body, which has increased the demand for it.

Younger women look to older women for guidance and mentorship. They rely on being able to trust their foremothers as sisters in the cause for women’s health. But the increased scarcity of the fertile female body, combined with IVF technology that allows for egg harvesting and surrogacy, creates conflict between generations of women. Older women with more power and resources put their interests ahead of younger women’s and make up for their past mistakes or misfortunes by risking the health and well-being of their successors.

The attack comes from close range—dressed in words of altruism and generosity. The women who seek other women’s children often carried the torch for gender equality, women’s rights, and so many other wins for their side in the gender wars. Out of respect for their ambition and challenge to the glass ceiling, younger women feel pressured to give their children to older women as gestures of appreciation for their life trajectories. Perhaps these women anticipate a similar trajectory for themselves and donate away their children in hopes that someone will do the same for them in the future—a form of paying it forward.

Our gay friends and family members may now also be after our daughters’ bodies. These are the only men in the world we thought we could trust because they weren’t interested in our bodies. That is, until they grew older and discovered they wanted to be parents. Today, more and more often, gay men are using egg donors and surrogates to create motherless children on purpose.

Toleration of these attempts to create families follows a timeline of slipped slopes and fallen barriers. If heterosexual couples can use sperm donors to create children who are separated from their biological fathers, so the logic goes, then lesbians should be able to do the same thing. To them, it’s not biology that matters—kids just need two parents. And if lesbians use sperm donors to create fatherless children, then it’s only equal and fair for gay men to be able to use egg donors and surrogates to create motherless children too. Because again, it’s not biology that matters; kids just need two parents. At present, all those who believe in gender equality rather than gender complementarity are being urged to accept this often violent (against women) form of third-party reproduction.

Proponents of redefining marriage call marriage equality “the civil rights struggle of our time.” TV shows like The New Normal promote surrogacy arrangements with dialogue like “a family is a family, and love is love.” Characters that criticize the use of surrogacy and egg donation are explicitly depicted as unsympathetic, racist, closed-minded bigots.

What these shows (and other memes) do is insist that in order to be a friend to gay people, one must approve, or at least stay neutral toward, all forms of third-party reproduction.

So now, young women must do more than simply defend themselves against aggressive heterosexual males who want to use them for sex. They must also navigate a world filled with new, never-before-seen predators—people they thought they could trust—who aggressively target them for their eggs and wombs.